Association between serum alpha-Klotho and severe abdominal aortic calcification among civilians in the United States.

BACKGROUND AND AIMS: Abdominal aortic calcification (AAC) has been recognized as an independent predictor of cardiovascular disease (CVD) incidence and mortality. The aim of this cross-sectional study is to investigate the relationship between serum α-Klotho, an anti-aging hormone, and severe AAC in United States (US) civilians, which was not documented before. METHODS AND RESULTS: The data were obtained from the 2013-2014 National Health and Nutrition Examination Survey (NHANES), which included 2267 individuals aged 40-79 years. Serum α-Klotho concentration, categorized into four quartiles, was examined by enzyme linked immunosorbent assay (ELISA). AAC was quantified by the Kauppila score system based on dual-energy X-ray absorptiometry. The association between serum α-Klotho and severe AAC was determined by multivariable logistic regression models. After adjusting for multiple covariates, the odds ratios (OR) (95% CI) of severe AAC for participants in serum α-Klotho quartiles 2-4 were 0.83 (0.52, 1.32), 0.56 (0.34, 0.94), and 0.54 (0.32, 0.92), respectively, compared with those in quartile 1 (P for trend = 0.007). The association between serum α-Klotho and severe AAC was stable in the different subgroups (all P for interaction＞0.05). CONCLUSION: In a sample of US adults, serum α-Klotho levels were negatively related to the risk of severe AAC. Our findings indicated that serum α-Klotho may become a promising tool to predict the incidence and prognosis of CVD.